Phonographic record



Patented M... 3, i927.

UNITED STATES PATENT OFFICE.

PAUL BALIE AND GUSTAV LEYSIEII'EB, OI TBOISDOBI', Gm.

PHONOGBAPEIO REOOBD.

Io Drawing. Application filed December 1, 1920, Serial 10. 487,635, and in Germany l'ebnu'y 18, 1930.

The phonographic records for talking machines and the like which are now in vogue are at the present produced entirely of a. substance whose principal component is shellac.

I These records ossess a number of serious drawbacks, as ibr exam 1c the impure tone which arises through the injuries done to the phonetic impressions when the records are used a number of times, the high price of the records or plates, due to the shellac that has to beimported. Further drawbacks are the great weight of the plates, their exceedingly reat frangibility and the imperfect repr notion of the music as regards the clearness and fulness of the sound. It is true that attempts have alread been made to use other materials for pr ucing sound.

records, but no record of practical valve has as et been produced Without shellac.

nother idea in this connection is disclosed in the German Patent No. 267,161. In accordance with this, shellac cannot be dis- 'pensed' with, but it is considered to be a' progressive step to enable the use of shellac or the like to be restricted to the core, whilst the outside coating of the same is made of cellulose esters or mixtures thereof. But these composite plates do not fulfil the requirements met by a homogenous sound market. Besides, even thew plates require a large amount of shellac which, if it can be got at all, under the conditions prevailing at the present day, isso difficult to procure that the avoidance of this raw material is a matter of great economic importance.

The present invention consists in providing a non-composite, homogeneous, uniform,

sound record made of cellulose esters and a considerable admixture of finely ground filling substance and an admixture of gelatinizing agents. The proportionate quantities of the said three com 'onents of the substance record and have not appeared upon the of which the plate 18 formed'is such that the v the emitted tone. They are very elastic, infrangible, of a very light weight and, as has already been pointed out, cost little to produce, because the materials that are hard to procure are dispensed with.

Experiments have shown that fibrous substances (cellulose, cotton, peat, cork and the like) make giarticularly good filling agents. A process or producing records or plates of this kind will now be described by way of is then wor ed up into a homogeneous mass which is rolled out into sheets. Plates are then stamped out of the sheets and finally the sound records are impressed on the plates. A specific example of a mixture showing the actual amounts of the components used is the following:

35 kgs. nitro-cellulose.

42 kgs. cellulose.

5 kgs. black earth-colour.

18 kgs. gelatinizing agent, such as methyl, ethyl, urea.

Qur invention broadly comprises the rovislon of a homogeneous sound record having as its essential ingredients a cellulose ester or an ester of a cellulose derivative, a gelatmizing agent, and a filling agent. In the above example, nitro-cellulose is given asan example of the cellulose constituent and methyl ethyl urea of the gelatinizing agent. I

We claim:

1. A homogeneous sound record for talkmg machines or the like consisting of cellulose nitrate, a filling material, and a gelatinizing agent, the filling material being present in a quantity greater than the cellulose nitrate, and the gelatinizing agent in a quantity greater than that required to gelatinize the nitrate.

2. A homogeneous sound record for talking machines or the like consisting of cellu lose nitrate, a filling material and methyl a tauantity greater than the cellulose nitrate ethyl urea adapted to act as a gelatinizing' an the methfil ethyl urea in a quantity 1 at required to gelatinize the agent. greater than t 3. A homogeneous sound record for talknitrate. 5 ing machines or the like consisting of a ce1 In testimony whereof we aflix our siglulose nitrate, a filling material and methyl natures. ethyl urea adapted to act as a gelatinizing DR. PAUL BALKE. agent, the filling material being present in DR. GUSTAV LEYSIEFFER. 

